Solvent accessible surface area (SASA) of proteins has always been considered as a decisive factor in protein
folding and stability studies. It is defined as the surface characterized around a protein by a hypothetical centre of a solvent
sphere with the van der Waals contact surface of the molecule. Based on SASA values, amino acid residues of a protein
can be classified as buried or exposed. There are various types of SASAs starting from relative solvent accessibility to
absolute surface areas. Direct estimation of accurate SASAs of folded proteins experimentally at the atomic level is not
possible. However, the SASA of a native protein can be estimated computationally from the atomic coordinates. Similarly,
various simulation methods are available to compute the SASA of a protein in its unfolded state. In efforts to estimate
the changes in SASA related to the protein folding, a number of the unfolded state models have been proposed. In
this review, we have summarized different algorithms and computational tools for SASA estimations. Furthermore, online
resources for SASA calculations and representations have also been discussed in detail. This review will be useful for protein
chemists and biologists for the accurate measurements of SASA and its subsequent applications for the calculation of
various biophysical and thermodynamic properties of proteins.